クエン酸中毒症に関する実験的研究 (第1報) 凝血機序並びに心電図所見に及ぼす低Ca血症の影響

Abstract

The changes of serum Ca ion during infusion of a large dose of citric acid and its effects on whole blood clotting time, together with E. C. G. findings are experimentally studied.1) The theoretical equations by McLean and Hastings concerning the Ca ion concentration in a solution containing protein and citric acid, are developed further theoretically, and a method for its solution are described.A nomogram is constructed in which theoretical values of Ca ion concentrations can be obtained from the measured values of protein, total Ca and citric acid concentrations.2) When citric acid is administered by infusion at a rate of 2-6mg/kg/min., the concentrations of both serum total Ca and citric acid increase, 1 hour later reaching the maximum value at the end of infusion, but their values decrease again.The concentration of citric acid increases as rapidly as it is reduced, and a pyramidal curve is obtained having a peak at the end of infusion.3) Although the concentration of serum Ca ion shows no significant changes during the administration of citric acid at a rate of 2-6mg/kg/min., it is reduced as the concentration of total serum citric acid becomes elevated. However, it is restored as rapidly as the restoration of citric acid concentration.4) Whole blood clotting time, accompanied by the reduction of Ca ion concentration, may also be delayed, but promptly reaches the normal value with the restoration of Ca ion concentration.5) The concentrations of total Ca and Ca ion are quickly elevated by intravenous administration of CaCl2. During infusion of citric acid at a rate of 6mg/kg/min., an administration of 3-5cc of 2% CaCl2 solution prevents the tendency toward the reduction of Ca ion concentration.It is conceivable, however, that, if the intravenous administration of CaCl2 is inadequate as to the time or the dose, there may be a danger of increasing Ca ion.6) Liver resection has no significant effects on the metabolism of citric acid or of Ca ion concentration.7) During the infusion of citric acid, prolongation of QT and ST, and changes of T wave which suggest the appearance of hypocalcemia can be demonstrated by E. C. G.